Grow for Flavour: James Wong tells how to turbocharge taste

March 5th, 2015 by
Rhiannon James

See a strawberry and you might delight in the gleam of its ruby red skin, its evocative perfume or its delicate balance of tartness and sweetness. James Wong on the other hand, will be getting excited about its anthocyanins, volatile molecules and fragrant esthers.

And while most of us are really only thinking “Yum!” when we eat a particularly tasty carrot, James can tell you it’s thanks to a perfect balance between sugars and terpenes – bitter chemicals that apparently smell like turps.

Just as molecular gastronomy found a new approach to food by the rigorous appliance of science, so James, a self-confessed plant geek, has pulled on his metaphorical goggles and white coat to try to change the way we grow our fruit and vegetables so they fulfil the ultimate promise of home grown – amazing taste.

“When I do gardening programmes I’m often told, don’t talk about the science, viewers don’t want to see that, they just want to know exactly what to do. And yet when I’ve done talks all over the country, the one thing that everyone gets excited about is not the how to – it’s the why to,” explains James.

As with most of James’ projects, this new book, called Grow for Flavour, has been an arduous task – he chomped his way through 350 tomato varieties in two days as part of his trials to find the most flavoursome choices and waded through more than 2,000 scientific papers to find growing techniques that are proven to improve taste.

Some of the results though are rather fascinating. Gentle stroking and regular applications of aspirin might sound better for a headache than a harvest but stroking seedlings once a day can make them six times more resistant to cold and improve establishment rates by up to 70 per cent. Spraying tomatoes and other crops with aspirin, meanwhile, can increase sugars by 150 per cent and vitamin C by 50 per cent.

Credit: Jason Ingram

The nice thing about the book is that it’s full of good news. Being a lazy gardener is scientifically proven to improve the flavour of your harvest, according to James, because many of the chemicals responsible for flavour in fruit and vegetables are created by plants in response to stresses such as drought. Cutting back on the watering also concentrates flavours and nutrients – even in root crops such as beetroot and carrots, less water ups sugar content and increases polyphenols by up to 86 per cent.

There’s also the fact that as a general rule, according to James, the better a fruit or vegetable tastes, the better it is for you – now when have you ever been able to say that about food before?

A little of what you fancy . . .

“What I found, the more research I did, is that effectively everything you do to up flavour, ups nutrition,” he says. “In crops, effectively it’s all about concentration so when you make strawberries more concentrated, they taste better, but they’ve also got more vitamins. And in fact, nutrients are usually the things that contribute towards their flavour, or at least are signifiers of it. So part of the tartness of strawberries, which adds to their appeal, is from ascorbic acid which is vitamin C. And some of their fragrance compounds are breakdowns of their colour pigments which are antioxidants. So the stronger tasting a strawberry, the more likely it is to have high antioxidant compounds. I’m a botanist and I didn’t know that.”

And as it turns out, growing your own may just be vital to your health. Vegetables found in today’s supermarkets are lower in nutrients than those harvested 60 years ago, according to research by Dr. Donald Davis of the University of Texas. Perhaps this goes some way to explaining why we now need our ten-a-day not five.

James tips for growing for flavour:

Variety

Credit: Jason Ingram

The single biggest influence on whether your fruits and vegetables are delicious or dull, is the variety you choose, according to James. To find the best, he says, there is no real alternative to trial and error as descriptions in catalogues can be misleading. Thankfully, though, James has done plenty of trialling for this book and despite the size of the task, he says the winners were easy to spot. “It does really stand out if something is fantastic, you instantly know. It’s like standing in a tube carriage and trying to pick out a Hollywood star – it’s not difficult.” Variety can also make a surprising difference to healthiness. Blueberries for example, are regularly touted as a superfood but it seems some are more super than others. A variety called ‘Rubel’ has three times more anthocyanins than supermarket standard ‘Bluecrop’ and our native bilberry (Vaccinium myrtillus) has 20% more antioxidant activity even than ‘Rubel’.

Heirlooms

One finding that may cause consternation is that heritage fruits and vegetables do not necessarily taste better than their modern cousins – in fact, new varieties bred for flavour may have an advantage. “In the twentieth century, there was a lot of breeding work that was primarily directed at yield. That doesn’t mean necessarily that modern varieties are worse, it just means that modern varieties bred entirely for yield are worse,” he says. “The date a variety was bred really has nothing to do with its nutritional content or its flavour.” He also notes that the word ‘heritage’ itself has lost some of its savour, becoming a catch-all for any variety that tastes good and looks a bit unusual. “I keep hearing about heirloom varieties that are famously delicious such as ‘Green Zebra’ and ‘Sungold’ but if you look at the dates they were bred – ‘Sungold’ in the 1990s and ‘Green Zebra’ in the 1980s – if those are heirlooms then I’m ancient,” he jokes.

Growing

Most standard growing advice for gardeners is more likely to zap flavour than harness it, according to James because it is based on nineteenth century methods designed to increase yields. Part of the fun of the book is to see which oft-quoted methods survive the microscope. James has been convinced that pruning is worthwhile. “I never used to prune fruit trees because frankly, I don’t have that much time,” he admits. “But if you look at some studies that show an apple at the top of the tree has up to double the antioxidants and is significantly sweeter than those at the bottom, then you think, ok, I might just spend that five minutes pruning.” Conscientiously applying commercial liquid plant food, on the other hand, he says, is equivalent to bringing up your plants on junk food and will boost yields but knock down flavour.

“The big one is tomatoes,” he says. “If you look at standard advice on how to grow tomatoes, it’s almost like a lesson in how to reduce their flavour compounds and make them taste watery. I’ve seen gardening television presenters who tell you to water your tomatoes every day, with high nitrogen food, in pots in a greenhouse – that’s literally every rule to make them taste of nothing.”

There are plenty of new ideas in the book to stir things up a bit at the allotment – how about feeding your newly-transplanted trees with molasses (helps roots to establish and increases ability to withstand environmental stresses by more than 50%) or applying (very dilute) salt water to your tomatoes (improves flavour and can cause levels of vitamin C, lycopene and beta-carotene to increase by as much as 35%)?

And while gardening rules are usually churned out as gospel, James points out that you might approach things differently depending on what result you want to achieve. So for the most succulent, tender salad, go with conventional wisdom but if you like your leaves with a peppery punch, do the exact opposite – grow in sun, be stingy with the water and harvest when leaves are mature.

Harvesting

Harvesting it turns out is a science in itself – picking at the point of optimal ripeness can make a huge difference to flavour and potentially nutrients. James gives the example of strawberries which picked pink, have only 1% of the aroma compounds found in ripe red fruit and one and a half times less sugar. Even the time of day counts: salads are best harvested in the morning when they’re at their most succulent but fruits should be gathered in the late afternoon when sugars and aroma compounds are most concentrated.

Storage

After you’ve plucked your prize produce triumphantly from the ground, what do you do next? If the answer is run to the nearest cooker, you might want to take a breath. Some vegetables, such as winter squash and sweet potatoes get better with keeping because their starches then have time to break down into sugars. In fact, the sugars in butternut squash have been shown to more than quadruple after three months’ storage. Where you put your produce also matters – tomatoes can continue to produce flavour compounds for several days after they’re picked but not if they’re put in the fridge.

Grow for Flavour by James Wong, published by Mitchell Beazley, is out now

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